1. Field of the Invention
The invention relates to a vehicle power supply unit including a plastic part.
2. Description of Related Art
An insulating material mainly made of plastic is conventionally used for forming a part used in a vehicle power supply unit for an electric vehicle or the like. Also, some plastics are made conductive and used as conductive materials. For example, Japanese Laid-Open Patent Publication No.2000-17179 discloses a fuel cell including a separator made of conductive plastic (resin). Also, a secondary battery whose battery case is made of plastic is known.
As is widely known, various environmental measures are taken for disposing of regular vehicle parts. Likewise, when disposing of a plastic part for use in electric vehicles, such as a plastic separator of a fuel cell, some environmental measures need to be taken. However, when disposing of such a plastic part of a vehicle power supply unit, the following problem is concerned. That is, when plastics (waste plastics) are buried in the ground together with other waste materials, they remain undecomposed semi-permanently in the ground. Also, when the plastics are burnt using an incinerator, or the like, the useful life of the incinerator reduces owing to high energy required for burning the plastics, or toxic substances are released into the air, thus damaging the environment.